益生菌发酵乳模拟胃肠液环境下抗氧化活性

为间接评价益生菌发酵乳在人体内的抗氧化活性，分别采用嗜热链球菌（Streptococcus thermophilus）、德氏乳杆菌保加利亚亚种（Lactobacillus delbrueckii subsp. bulgaricus）、动物双歧杆菌（Bifidobacterium）BB12及嗜酸乳杆菌（Lactobacillus acidophilus）制备SL、SL+BB12、SL+LA三种发酵乳，并对其冷藏过程中模拟胃肠液环境下对ABTS、DPPH自由基的清除能力进行了测定。结果表明，三种发酵乳随冷藏时间的延长其抗氧化活性都逐渐降低，添加菌种BB12和LA的发酵乳抗氧化活性下降的幅度小于SL发酵乳，在相同的冷藏时间下模拟胃肠液环境后抗氧化活性都较原发酵乳降低，但添加益生菌BB12和LA发酵乳在模拟胃肠液环境下抗氧化活性高于SL发酵乳，其中BB12高于LA。SL、SL+BB、SL+LA发酵乳冷藏7 d时对ABTS自由基最大清除率分别为46.21%、58.54%、51.99%，对DPPH自由基最大清除率分别为42.17%、53.34%、49.48%。

Antioxidant activity of fermented milk with probiotics in simulated gastrointestinal fluid

In order to indirectly evaluate the antioxidant activity of fermented milk with probiotics in vivo, three kinds of fermented milk (SL, SL+BB12, SL+LA) were prepared by Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Bifidobacterium BB12, Lactobacillus acidophilus. And the scavenging capacity of the three fermented milk on ABTS and DPPH free radicals in simulated gastrointestinal fluid during cold storage was detected. Results showed that the antioxidant capacity of the three fermented milk was gradually decreased with the extension of cold storage time. The decrease ranges of antioxidant activity of fermented milk with strain BB12 and LA were less than that of fermented milk with SL. In the same cold storage time, the antioxidant activity of fermented milk in the simulated gastrointestinal fluid was lower than that of the original fermented milk, but the antioxidant activity of fermented milk with strain BB12 and LA in the simulated gastrointestinal fluid was higher than that of fermented milk with SL, and the antioxidant activity of BB12 was higher than that of LA. The maximum scavenging rate of fermented milk with SL, SL+BB and SL+LA on ABTS free radicals were up to 46.21%, 58.54% and 51.99%, respectively, and the maximum scavenging rate on DPPH free radicals were up to 42.17%, 53.34% and 49.48%, respectively.